I have a Toshiba Satellite S55-A5275 and it will not boot up on the battery. And if you un-plug it while running it will turn off immediately. Th.e battery icon on the task bar says the battery is fully charged at 100%. Any ideas???
I can thing of a couple of possibilities. The battery may in fact be bad is such a way that it can't supply the current needed to run the machine by itself. Another possibility is that the laptop power supply on the motherboard is broken such that it can charge the battery but not draw power from it. Toshiba should have a battery diagnostic you can run, but it likely requires you to unplug external power. There are certainly other possibilities but if you don't want to take it to a shop, you can try replacing the battery. If you have to open the machine to do that, use great care and anti-static (ESD) precautions. It is easy to break something. Of course, you may find you wasted your money on a replacement battery. How old is the machine? If it is several years old, they battery is likely about worn out anyway.